One of the most popular adds of the week, Arenado was called up from Triple-A Colorado Springs on Sunday and will serve as the Rockies' starting third baseman moving forward. The 22-year-old saw his stock fall a bit last year due to some underwhelming numbers in the Texas League and concerns over his makeup, but he played well this spring and was hitting .364 with three home runs, 11 doubles and 21 RBI over his first 18 games with the Sky Sox. Arenado is more of a doubles guy than a power hitter at this point, but playing half of his games in Coors Field should help his overall numbers. Maybe he won't be a top-12 third baseman the rest of the way, but he should be useful in most mixed formats.

Smith is striking out at a prodigious rate, but he has been very productive for the A's in the early part of the season, hitting .302 with three home runs, seven doubles and 16 RBI through 24 games. While he has produced in a small sample against southpaws, that hasn't been the case for most of his career. With that in mind, he's best utilized in daily leagues where you can plug him in against right-handers. Still, he offers plenty of pop and should see plenty of playing time while Coco Crisp is sidelined with a hamstring injury.

Garza's return from a lat injury hit a brief snag last week due to what was described as a "dead arm," but he was able to throw 42 pitches over 2 2/3 innings Wednesday in his first minor league rehab start with Double-A Tennessee. The 29-year-old right-hander is expected to require at least three more appearances in the minors, which should put him on track to join the Cubs' rotation by the end of May. Garza was limited to just 18 starts last season due to a stress reaction in his elbow, but he owns a 3.84 ERA and 1.29 WHIP for his career and should be stashed in a DL-spot in all formats. If he's effective upon his return, the Cubs could ship him to a contender, which could only help his fantasy value for the rest of the season.

OK, so maybe this pick has lost a little bit of momentum after Hernandez gave up a go-ahead three-run homer to Brandon Belt on Wednesday night, but closer J.J. Putz still has plenty of issues of his own. The veteran right-hander has blown four saves in his first nine chances this season after going 32-for-37 in save chances last season and 45-for-49 in 2011. He has also shown poor control and diminished velocity, which isn't what you want to see from someone with an injury history. Meanwhile, Hernandez brings the heat and has quietly been one of the game's best relievers since the start of 2011. Both have rather fluky home runs rates right now, so we could just be dealing with some small sample panic, but Hernandez is a decent option if you want to speculate. Matt Reynolds and Heath Bell could be worth adding in deeper formats.

Martin began the season hitless over his first six games, but he's hitting .343 (23-for-67) with six home runs, six doubles and 10 RBI over his last 18 contests. Of course, the 30-year-old backstop hit just .211 last season and hasn't batted higher than .250 since way back in 2008 as a member of the Dodgers, so we should probably expect some regression in that department in the days ahead. But don't forget that only J.P. Arencibia, Matt Wieters, Carlos Santana and Mike Napoli have more home runs among catchers since the start of 2011. Martin is also capable of mixing in a stolen base from time to time. He's a perfectly acceptable option in deeper leagues and two-catcher formats.

Some folks gave up on Morales after he drove in just three runs during a 14-game stretch through the end of April, but he showed some signs of life Wednesday night against the Orioles by going 3-for-5 with a double and three RBI. While the 29-year-old switch-hitter hasn't shown much power so far, his track record suggests that it should come soon. Remember, he hit 22 homers in 134 games last season in his long-awaited return from a freak leg injury and showed increased power production as the year moved along. And while the dimension changes at Safeco Field haven't made the stadium a hitter's haven, it's not like Angel Stadium was a bandbox. I'd like him more with a better supporting cast -- and he could be a potential trade candidate later this summer -- but he should be fine.

Kyle Kendrick SP, PhilliesMIXED LEAGUES(Yahoo: 36 percent owned)

Don't look now, but Kendrick might be turning into a pretty good pitcher. The 28-year-old right-hander has a 2.41 ERA through four starts this season and a 2.42 ERA in 15 starts dating back to August 14 of last season. As my HardballTalk colleague Bill Baer notes, he's not doing it with mirrors, as his strikeout rate has jumped since he started throwing fewer cutters and increasing the use of his change-up and two-seamer. I don't expect his ERA to stay where it is right now, but don't be surprised if he is relevant in mixed leagues for the entire season.

Jason Kubel OF, DiamondbacksMIXED LEAGUES(Yahoo: 47 percent owned)

It feels like Kubel became somewhat of a forgotten man after his recent quad injury, but fantasy owners should take advantage. The 30-year-old smacked a two-run homer in his second game back from the disabled list on Tuesday night and is now hitting .317 (13-for-41) with three home runs and eight RBI through 11 games this season. The batting average isn't likely to last, but Kubel had 30 home runs and 90 RBI in 141 games last season. Considering that he plays half of his games in one of the most hitter-friendly ballparks in the game, there's no reason that he should be available in this many leagues right now.

Zack Cozart SS, RedsMIXED LEAGUES(Yahoo: 31 percent owned)

Do I think that Cozart should be hitting anywhere near the top of the Reds' lineup? Absolutely not. But it's not a bad place for him to be in fantasy leagues. The 27-year-old is batting just .200 through 26 games, so I understand the hesitation, but he already has four home runs and 12 RBI. That puts him on pace to easily top the 15 homers and 35 RBI he produced as a rookie last year. I also think he's capable of stealing more than four bases. His poor plate discipline means that he should continue to be a drag in the batting average department, but those looking to fill a middle infielder (MI) spot could do worse.

Ryan Raburn 2B/OF, IndiansMIXED LEAGUES(Yahoo: 10 percent owned)

Raburn might be the hottest hitter on the planet right now. No, wait, I'm positive that he is. The 32-year-old has 12 hits in his last 14 at-bats, including four home runs and nine RBI. While he's coming off a season in which he batted just .171/.226/.254 (!) in 222 plate appearances, it's not like he hasn't been useful in fantasy leagues before. He produced at least 14 home runs every season from 2009-2011. That's useful pop from a middle infielder (MI) spot. He's worth trying in deeper leagues, at least until Michael Bourn returns from his finger injury.

Kevin Slowey SP, MarlinsMIXED LEAGUES(Yahoo: 7 percent owned)

Slowey was mentioned in our NL-only recommendations a couple of weeks ago, but he has earned a promotion after posting a surprising 2.15 ERA, 1.01 WHIP and 29/6 K/BB ratio in 37 2/3 innings across six starts. Not bad for someone who didn't pitch in the majors last season. His strand rate and batting average on balls in play (BABIP) are both a bit fortunate, but he still has excellent control and the strikeout rate could stick now that he's in the easier league. And his fly ball tendencies are less of a concern at the cavernous Marlins Park. The light-hitting Marlins have only provided six runs of support in his six starts, so there's not much in the way of win potential, but he should help in WHIP and could be an interesting option in leagues which use quality starts as a category. Keep an eye on him, at the very least.

Matt Joyce OF, RaysMIXED LEAGUES(Yahoo: 6 percent owned)

After struggling to the tune of a .185 batting average through 18 games, Joyce has turned things on over the past week by collecting four home runs and seven RBI in his last five games. The 28-year-old will likely sit against most southpaws, but he had 17 home runs in 124 games last season and 19 in 141 games in 2011. He's also shown that he's capable of reaching double-digit stolen bases. I like him more in daily formats, but he simply shouldn't be available in this many leagues right now.

Kevin Gausman SP, OriolesAL LEAGUES(Yahoo: 1 percent owned)

FOX Sports' Ken Rosenthal passed along an interesting nugget on Wednesday night that Gausman "might not be in the minors much longer." It shouldn't come as a major shock, as last year's No. 4 overall pick has followed up an impressive spring with a 3.77 ERA and a stingy 29/1 K/BB ratio in 28 2/3 innings over his first five starts this season with Double-A Bowie. Freddy Garcia and Jair Jurrjens are probably next in line for the O's rotation, but it's possible that Gausman could get an opportunity in June if he continues to perform. Some patience may be required, but the 22-year-old should be stashed away if you have some roster flexibility.

Chris Nelson 2B/3B, YankeesAL LEAGUES(Yahoo: 2 percent)

After being designated for assignment by the Rockies over the weekend in order to make room for Nolan Arenado, Nelson was acquired by the Yankees on Wednesday night in exchange for a player to be named later or cash considerations. It's a pretty good landing spot for the 27-year-old, who could see semi-regular playing time at third base while Kevin Youkilis recovers from a back injury. Nelson enjoyed most of his success at Coors Field last season, but it's not like Yankee Stadium is a terrible environment for hitters. He could be a nice short-term play.

Mike Carp 1B/OF, Red SoxAL LEAGUES(Yahoo: 1 percent owned)

Carp has made the most out of his limited opportunities thus far, hitting .480 (12-for-25) with two home runs, five doubles, two triples and seven RBI in 13 games. That's right, nine out of his 12 hits have been for extra bases. The 26-year-old only hit .213 with five homers and a .654 OPS in 189 plate appearances with the Mariners last season, but I'm willing to give him somewhat of a mulligan since he was bothered by hip and shoulder injuries for most of it. David Ortiz's return could make it more difficult for him to find at-bats, but he's worth keeping around in case Shane Victorino has a setback with his recent back issue.

A.J. Ramos RP, MarlinsNL LEAGUES(Yahoo: 0 percent owned)

Ramos took the loss Wednesday against the Mets by giving up a go-ahead three-run homer to Jordany Valdespin, but he has still been very impressive in the early part of his career. After enjoying some success as a September call-up last year, the hard-throwing 26-year-old has a 3.38 ERA and 18/6 K/BB ratio through 16 innings this season. Ramos averaged 12.3 K/9 over four seasons in the minors, so he has the kind of swing-and-miss stuff managers look for in a potential closer. He could get his chance if Steve Cishek continues to struggle or is placed on the trading block later this summer.

Charlie Morton SP, PiratesNL LEAGUES(Yahoo: 0 percent owned)

Morton is inching closer to making his return from Tommy John surgery, as Pirates manager Clint Hurdle said Wednesday that he should join the team's rotation somewhere around May 15. The 29-year-old right-hander owns a 2.08 ERA and 9/3 K/BB ratio in 13 innings through three rehab starts and induced grounders from 10 out of the 22 batters he faced in his most recent outing. That's what we like to see. Morton will never be a big strikeout guy and command is often shaky after Tommy John surgery, but he could be a productive option in NL-only leagues the rest of the way.

Marcell Ozuna OF, MarlinsNL LEAGUES(Yahoo: 0 percent owned)

Giancarlo Stanton was placed on the disabled list earlier this week due to a Grade 2 hamstring strain, so the Marlins plucked Ozuna out of Double-A and plan to use him as their starting right fielder for now. The 22-year-old has hit at least 22 homers in each of his last three seasons in the minors, so he has serious power potential, but he has just 47 plate appearances above A-ball and has shown shaky plate discipline. I think he'll struggle to hit for a high batting average, but he could run into a few homers until Stanton is ready to return in a month or so.